1. Field of the Invention
The present invention relates to a nozzle rotating apparatus of a module head of a surface mounting device, and more particularly to a nozzle rotating apparatus of a module head of a surface mounting device which is capable of correcting an error possibly occurring when a nozzle picks up an electronic component and places it on a printed circuit board.
2. Description of the Background Art
FIG. 1 is a plan view of a module head of a surface mounting device adopting a nozzle rotating apparatus in accordance with a conventional art, and FIG. 2 is a side view of the module head of FIG. 1.
Conventionally, as shown in FIGS. 1 and 2, a module head of a surface mounting device employing a nozzle rotating apparatus roughly includes a head 10 and a nozzle rotating apparatus 15.
The head 10 includes a shaft 11, a vertical movement unit 12 connected with the shaft 11 and an air opening and closing unit 13. The nozzle rotating apparatus 15 includes a rotatable motor 1a and a plurality of timing belts 1b. 
A nozzle 11a is installed at the other side of the shaft 11. That is, the nozzle 11a is assembled at the other side of the shaft 11 installed penetrating the inner side of the vertical movement unit 12.
A guide pin 11b is disposed to prevent the shaft 11 from rotating rightward and leftward when the shaft 11 is moved vertically.
The shaft 11 is rotatable in a vertical direction by the vertical movement unit 12 and picks up an electronic component (not shown) when the nozzle 11a connected with one side of the shaft 11 is moved downwardly by the vertical movement unit 12.
The nozzle 11a picks up or places the electronic component according to operation of flowing in and flowing out of air which is supplied from the air opening and closing unit 13. When the nozzle 11a picks up the electronic component, it moves the electronic component to a vision unit (not shown) to thereby sense a picking position of the electronic component and discriminate whether there is an position error. In case that the nozzle 11a fails to pick up the electronic component accurately, the nozzle 11a needs to be rotated minutely and precisely.
The nozzle rotating apparatus 15 transmits the rotating force generated by the rotatable motor la to the plurality of timing belts 1b assembled at the rotational centering shaft 1c, and the timing belts 1b transmits the rotating force generated by the rotatable motor 1a to gears (not shown) combined with each engated shaft 11. Then, as the gears installed at each shaft 11 are rotated upon receiving the rotating force through the timing belt 1b, the shaft 11 is rotated, and according to the rotation of the shaft 11, the nozzle 11a is rotated.
However, the conventional nozzle rotating apparatus has disadvantages in that, since it employs the timing belt, when the timing belt is used for a long time, it is abraded. Abrasion of the timing belt causes an error between gears, leading to an occurrence of a backlash. Then, the position correction of the electronic component is not made accurately, and the durability of the nozzle rotating apparatus is shortened.
Therefore, an object of the present invention is to provide a nozzle rotating apparatus of a module head of a surface mounting device by which in case that a module head erroneously picks up a component, a shaft is minutely rotated to correct an error of a nozzle position, to thereby pick up the component accurately.
Another object of the present invention is to provide a nozzle rotating apparatus of a module head of a surface mounting device by which a backlash is prevented from occurring when an error of a nozzle position is corrected and a linear motor, a rack and a pinion are easily assembled.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a nozzle rotating apparatus of a module head of a surface mounting device for picking up an electronic component and placing it at a predetermined position, including: a head movable in a predetermined direction along an upper portion of a substrate and having at least one shaft; a driving means for driving the head; a nozzle mounted at a lower predetermined portion of the head to pick up and place the electronic component; pinions installed at the outer periphery of the shaft installed at a predetermined portion of the head; a rack engaged with the pinions; and a driving force transmitting means for moving the rack to a predetermined direction.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.